The broad objective of the study is to provide the necessary framework for a rational - smart development of agents to intervene and or repair skin damage due to UV radiation. The hypothesis;to be tested is that nanodelivery of liposome encapsulated antioxidants to the skin is superior to liposome micron size delivery Specific aims include: Develop a dose - response model for the progression of damage induced by UV radiation to skin. Test the efficacy of prevention or repair of damage by delivering antioxidants encapsulated in liposome's at the micro and nanoscale. Encapsulated liposomes of various vitamins down to the nanoscale are being prepared and tested. The skin models start from human skin explants and progress to the hairless mouse animal model to establish response at a systemic level. Damage to the skin will be characterized by looking at early markers of UV damage, such as rate of pro-collagen synthesis, and expression of matrix metalloproteases. The proposed study will track damage caused by UV in the presence and absence of antioxidants delivered through micro and nanodelivery systems. This project will achieve the outlined goals by synergizing and linking expertise between Thomas Jefferson Medical School, Drexel University and the candidate and mobilizing resources currently available at the University or in industry, to create a Skin Research Initiative. The candidate brings expertise in UV degradation mechanisms and antioxidant stabilization of macromolecules that will be linked with the expertise of the mentors;in Dermatology and Skin Biology (Jouni Uitto and Urich Rodeck), in Photobiology (Douglas Brown arid Nikiforos Kollias), in Encapsulation and Delivery (Margaret Wheatley ), and in Nariotechnology (Kambiz Pourrezaei).